Schizothoracins are a group of cyprinid fishes distributed throughout the Qinghai–Tibet Plateau, which can be classified in three grades: primitive, specialised and highly specialised according to adaptation ability to plateau environments. As the only specialised schizothoracins in Xinjiang, China, Diptychus maculates
and Gymnodiptychus dybowskii
are ideal materials for adaptive evolution research. Based on single-nucleotide polymorphism (SNP) loci detected by specific-locus amplified fragment (SLAF) technology, the genome-wide genetic diversities of these two species from nine sites in Xinjiang were evaluated. D.maculates
in the Muzat River (BM) and G. dybowskii
in the Kaidu River (LKG) presented the lowest genetic diversity levels, whereas D. maculates
in the Kumarik River (BK) and G.dybowskii
in the Kashi River (LK) were just the opposite. Cluster and principal component analysis demonstrated a distant genetic affinity between D. maculates
in the Tashkurgan River (BT) and other populations. Outlier SNP loci were discovered both in D. maculates
and G. dybowskii
. The coalescent Bayenv and latent factor mixed model (LFMM) methods showed that a total of thirteen and eighteen SNPs in D. maculates
were associated with altitude and temperature gradient, respectively. No intersection was revealed in G. dybowskii.
The results indicated that D. maculates
was subject to much greater divergent selection pressure. A strong signal of isolation-by-distance (IBD) was detected across D. maculates
(Mantel test, rs = 0.65; p
= 0.05), indicating an evident geographical isolation in the Tarim River. Isolation-by-environment (IBE) analysis implied that temperature and altitude selections were more intensive in D. maculates
, with greater environmental variation resulting in weak gene flow.
This is an open access article distributed under the Creative Commons Attribution License
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.